WO2018088191A1

WO2018088191A1 - Ceramic substrate and method for manufacturing ceramic substrate

Info

Publication number: WO2018088191A1
Application number: PCT/JP2017/038264
Authority: WO
Inventors: 洋輔三野
Original assignee: 株式会社村田製作所
Priority date: 2016-11-11
Filing date: 2017-10-24
Publication date: 2018-05-17
Also published as: JP6743903B2; US20210227690A1; CN109923950A; US10999927B2; CN109923950B; JPWO2018088191A1; US20190254162A1

Abstract

This ceramic substrate is provided with a plurality of electrodes, and interelectrode wiring that connects the electrodes to each other, said electrodes and interelectrode wiring being on an electronic component mounting surface. The ceramic substrate is characterized in that, on the electronic component mounting surface, a resist is disposed over the interelectrode wiring.

Description

Ceramic substrate and method for manufacturing ceramic substrate

The present invention relates to a ceramic substrate and a method for manufacturing a ceramic substrate.

As a ceramic substrate, there is a substrate on which one surface is connected to a mother board and a plurality of electronic components are mounted on the other surface.

Patent Document 1 discloses a method for applying a cover coat to electrodes on the surface of a ceramic multilayer substrate in order to increase the adhesion strength between the substrate and pads (electrodes). Specifically, a method is disclosed in which a cover coat is printed on a film sheet having good releasability, and the film sheet and a ceramic green sheet on which an electrode is printed are bonded and pressed.

JP-A-9-223870

When a plurality of electronic components are mounted on a ceramic substrate, electrical connection between electrodes for mounting the plurality of electronic components may be performed by wiring (interelectrode wiring) formed on the electronic component mounting surface.
In the method described in Patent Document 1, the portion to which the cover coat is applied is an electrode, but it is not considered to cover the electrode wiring.
When the electrode is covered with a cover coat and the inter-electrode wiring is not covered, there is a problem in that the solder spreads between the electrodes during component mounting.

As a method for providing electrodes and inter-electrode wiring on the electronic component mounting surface, and further providing a cover coat on an appropriate part, the conductive paste is printed on the electronic component mounting surface to provide the electrodes and inter-electrode wiring, and the cover A method of printing a resist pattern to be a coating can be considered.
However, this method has a problem that the resist pattern is blurred because there is a step due to the electrodes and the inter-electrode wiring at the time of printing the resist pattern.

The present invention has been made in order to solve the above-described problem, and prevents the solder from spreading between the electrodes during mounting of the component, and prevents the resist pattern from bleeding between the electrodes. It is an object of the present invention to provide a method for manufacturing a ceramic substrate in which a resist serving as a cover coat is formed on a wiring.

The ceramic substrate of the present invention is a ceramic substrate in which a plurality of electrodes and inter-electrode wiring for connecting the electrodes are provided on an electronic component mounting surface, and a resist straddling the inter-electrode wiring is provided on the electronic component mounting surface. It is arranged.
If the resist straddling the inter-electrode wiring is disposed on the electronic component mounting surface, it is possible to prevent the solder from spreading between the electrodes during component mounting.

In the ceramic substrate of the present invention, the surface of the resist straddling the interelectrode wiring is preferably flat.
When the resist surface is flat, workability at the time of electronic component mounting is enhanced.

In the ceramic substrate of the present invention, the cross-sectional shape of the electrode and the inter-electrode wiring has a front surface, a back surface, a front surface corner portion having an R chamfered shape from the front surface to the back surface direction, and from the back surface to the front surface direction. Oppositely, it is composed of a back corner portion having an R chamfered shape, and the curvature radius of the back corner portion is preferably larger than the curvature radius of the front surface corner portion.
When the shape of the inter-electrode wiring is such a shape, it is possible to alleviate electric field concentration at the end of the inter-electrode wiring and realize better transmission characteristics.

Another aspect of the ceramic substrate of the present invention is a ceramic substrate in which an electrode is provided on an electronic component mounting surface, and the electrode is divided into a plurality of electrodes by straddling the electrode on the electronic component mounting surface. The resist to be arranged is arranged.
In this aspect, even when the inter-electrode wiring is not provided on the electronic component mounting surface, the electrode itself can be divided into a plurality of electrodes by arranging the resist straddling the electrodes. And it can be set as the electronic device which each mounted the electronic component in the some electrode.
Also in this aspect, it is possible to prevent the solder from spreading between the electrodes during component mounting.

The method for producing a ceramic substrate of the present invention comprises a step of preparing a ceramic green sheet provided with a plurality of electrodes and an inter-electrode wiring connecting the electrodes on the electronic component mounting surface, and a resist having a resist pattern provided on the surface. A step of preparing a sheet, and the resist sheet is placed and pressure-bonded so that the resist pattern overlaps an electronic component mounting surface of the ceramic green sheet, and the resist is placed so that the resist of the resist sheet straddles the inter-electrode wiring. And a transferring step.

In the manufacturing method, a resist straddling the electrode wiring is formed by transfer from a resist sheet provided with a resist pattern.
This method prevents the resist from bleeding.
Also, since the inter-electrode wiring is pushed into the ceramic green sheet by the crimping at the time of transfer, the portion of the resist straddling the inter-electrode wiring is prevented from becoming higher than the surrounding after the transfer of the resist. There is also an effect that the coplanarity of can be increased.

In the method for producing a ceramic substrate of the present invention, a resist pattern is printed on a release film, the release film is further pressure-bonded to a transfer sheet, and the release film is peeled off to transfer the resist pattern to the transfer sheet. Preparing a resist sheet, placing a resist sheet composed of a transfer sheet on which the resist pattern is transferred, and placing the resist pattern on the electronic component mounting surface of the ceramic green sheet, and then pressing the resist sheet. It is preferable that the resist is transferred so that the resist on the transfer sheet is stripped and straddles the inter-electrode wiring.

Further, in the method for manufacturing a ceramic substrate of the present invention, a resist pattern is prepared by printing a resist pattern on a baking sheet made of a material that is burned off at the baking temperature of the ceramic green sheet, and the baking pattern on which the resist pattern is printed. A resist sheet made of a sheet is placed and pressure-bonded so that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet, and the firing sheet is burned out by firing the resist sheet together with the ceramic green sheet. It is preferable to transfer the resist so that the resist on the baking sheet straddles the inter-electrode wiring.

Further, in the method for producing a ceramic substrate of the present invention, a resist pattern is prepared by printing a resist pattern on a peeling sheet that can be peeled off after being pressed to the ceramic green sheet. From the peeling sheet on which the resist pattern is printed, The resist sheet is placed so that the resist pattern overlaps with the electronic component mounting surface of the ceramic green sheet, and the resist sheet is peeled off, and the resist on the peeling sheet straddles the inter-electrode wiring. Thus, it is preferable to transfer the resist.

In the method for producing a ceramic substrate of the present invention, it is preferable that the thickness of the interelectrode wiring is 5 μm or more and 30 μm or less.
In the region where the thickness of the interelectrode wiring is within this range, the effect of increasing the coplanarity is particularly preferably exhibited.

Other aspects of the method for producing a ceramic substrate of the present invention include a step of preparing a ceramic green sheet having electrodes provided on an electronic component mounting surface, a step of preparing a resist sheet having a resist pattern on the surface, Placing the resist sheet so that the resist pattern overlaps with the electronic component mounting surface of the ceramic green sheet, and then transferring the resist so that the resist of the resist sheet straddles the electrodes. And
In this aspect, the resist can be transferred so that the resist of the resist sheet straddles the electrodes. And the ceramic substrate by which the electrode was divided | segmented into the some electrode can be manufactured. This method also prevents the resist from bleeding.
In addition, since the electrode is pushed into the ceramic green sheet by the crimping at the time of transfer, the resist portion straddling the electrode is prevented from becoming higher than the surrounding after the resist is transferred, and the coplanarity around the resist straddling the electrode is prevented. There is also an effect that can be increased.

In the ceramic substrate of the present invention, it is possible to prevent the solder from spreading between the electrodes during component mounting. According to the method for producing a ceramic substrate of the present invention, it is possible to produce a ceramic substrate in which resist pattern bleeding is prevented and a resist serving as a cover coat is formed on the interelectrode wiring.

FIG. 1 is a cross-sectional view schematically illustrating an example of an electronic device including a ceramic substrate according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing an example of the electronic component mounting surface of the ceramic substrate according to the embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view schematically showing a portion of the resist straddling the inter-electrode wiring, and corresponds to a cross-sectional view taken along line AA in FIG. FIG. 4A is an enlarged cross-sectional view schematically showing a resist portion straddling the inter-electrode wiring, and corresponds to a cross-sectional view taken along the line BB in FIG. FIG. 4B and FIG. 4C are cross-sectional views schematically showing an example of the cross-sectional shape of the interelectrode wiring. FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate. 6 (a), 6 (b) and 6 (c) are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate. FIG. 7A and FIG. 7B are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate. FIG. 8A, FIG. 8B, FIG. 8C, and FIG. 8D are process diagrams schematically showing a second aspect of the method for manufacturing a ceramic substrate. FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D are process diagrams schematically showing a third aspect of the method for manufacturing a ceramic substrate. FIG. 10A is a top view schematically showing a portion where a resist straddling the electrode is arranged in the ceramic substrate according to the embodiment of the present invention, and FIG. It is a top view which shows typically a mode that the electronic component was mounted in.

Hereinafter, the ceramic substrate and the method for producing the ceramic substrate of the present invention will be described.
However, the present invention is not limited to the following configurations, and can be applied with appropriate modifications without departing from the scope of the present invention.
A combination of two or more of the individual desirable configurations of the present invention described below is also the present invention.
Each embodiment shown below is an illustration, and it cannot be overemphasized that a partial substitution or combination of composition shown in a different embodiment is possible.

The ceramic substrate of the present invention is a ceramic substrate in which a plurality of electrodes and interelectrode wiring are provided on an electronic component mounting surface.
First, the provision of a plurality of electrodes and inter-electrode wiring on the electronic component mounting surface will be described with reference to the drawings of an electronic device including a ceramic substrate according to an embodiment of the present invention.

FIG. 1 is a cross-sectional view schematically illustrating an example of an electronic device including a ceramic substrate according to an embodiment of the present invention.
The electronic device 100 includes a plurality of electronic components (for example, a multilayer ceramic capacitor 110 and a semiconductor component 120 which are chip-shaped electronic components) mounted on an electronic component mounting surface 10 which is one main surface of the ceramic substrate 1.
The ceramic substrate 1 shown in FIG. 1 is a single-layer plate having a single ceramic layer 30, but may be a multilayer plate in which a plurality of ceramic layers are laminated.
A motherboard mounting electrode 45 is provided on the motherboard mounting surface 20 which is the other main surface of the ceramic substrate 1. The motherboard mounting electrode 45 is used as an electrical connection means when the electronic device 100 is mounted on a motherboard (not shown).

A plurality of electrodes 40 for mounting a plurality of electronic components are provided on the electronic component mounting surface of the ceramic substrate 1.
In the present specification, the term “electrode” means an electrode provided on the electronic component mounting surface for mounting the electronic component on the ceramic substrate, and is an electrical connection for mounting the electronic device on the motherboard. Motherboard mounting electrodes as means are not included.

An interelectrode wiring 50 is provided between the plurality of electrodes 40, and the plurality of electrodes 40 are electrically connected by the interelectrode wiring 50.
The interelectrode wiring 50 is a wiring provided on the electronic component mounting surface 10.
And the resist 60 is arrange | positioned so that wiring between electrodes may be straddled.
The positional relationship among the plurality of electrodes 40, the inter-electrode wiring 50, and the resist 60 on the ceramic substrate 1 will be described with reference to FIG.

FIG. 2 is a perspective view schematically showing an example of the electronic component mounting surface of the ceramic substrate according to the embodiment of the present invention.
On the electronic component mounting surface 10 of the ceramic substrate 1 shown in FIG. 2, six electrodes (electrode 40a, electrode 40b, electrode 40c, electrode 40d, electrode 40e and electrode 40f) for mounting the electronic component are shown. Three inter-electrode wirings (inter-electrode wiring 50a, inter-electrode wiring 50b, and inter-electrode wiring 50c) for electrically connecting the respective electrodes are provided.
Three resists (resist 60a, resist 60b, and resist 60c) are provided to straddle each inter-electrode wiring.
The resist straddling the inter-electrode wiring means that the width of the resist is larger than the wiring width of the inter-electrode wiring and the upper surface of the inter-electrode wiring is covered with the resist. As shown in FIG. 2, it is not necessary that the resist straddles all over the length of the interelectrode wiring, and there may be a portion where the resist does not straddle the interelectrode wiring in the vicinity of the electrode.

In the ceramic substrate of the present invention, it is preferable that the portion of the resist straddling the inter-electrode wiring is not higher than the surroundings, and the coplanarity around the inter-electrode wiring is high (flat). This will be described with reference to FIG.
FIG. 3 is an enlarged cross-sectional view schematically showing a portion of the resist straddling the inter-electrode wiring, and corresponds to a cross-sectional view taken along line AA in FIG.

As shown in FIG. 3, in the ceramic substrate 1, the interelectrode wiring 50 a is buried in the ceramic layer 30 in a portion where the resist 60 a is provided on the interelectrode wiring 50 a. As a result, the height of the upper surface of the resist 60a, the upper surface of the interelectrode wiring 50a not covered with the resist 60a, the upper surface of the electrode 40a, and the upper surface of the electrode 40b are aligned. That is, the coplanarity around the interelectrode wiring is high. Since the coplanarity of this part is high, workability at the time of electronic component mounting is enhanced.

FIG. 4A is an enlarged cross-sectional view schematically showing a resist portion straddling the inter-electrode wiring, and corresponds to a cross-sectional view taken along the line BB in FIG.
FIG. 4A shows that the wiring width of the resist 60a is larger than the wiring width of the interelectrode wiring 50a, and the upper surface of the interelectrode wiring 50a is covered with the resist 60a.
The surface of the resist 60a is flat. The flatness of the resist surface means that there is substantially no step between a portion where the inter-electrode wiring exists and a portion where the inter-electrode wiring does not exist.
As shown in FIG. 4A, the surface of the resist 60a becomes flat when the interelectrode wiring 50a is buried in the ceramic layer 30.

The cross-sectional shape of the inter-electrode wiring has a front surface, a back surface, a front surface corner portion having an R chamfered shape from the front surface to the back surface direction, and a back surface corner portion having an R chamfered shape from the back surface to the front surface direction. It is preferable that the radius of curvature of the rear corner portion is larger than the radius of curvature of the front corner portion.
FIG. 4B and FIG. 4C are cross-sectional views schematically showing an example of the cross-sectional shape of the interelectrode wiring.
FIG. 4B is an example of a cross-sectional shape including a flat portion having a constant conductor thickness.
4B, the cross-sectional shape of the inter-electrode wiring 50a includes a front surface 51 and a back surface 52 opposite to the front surface 51, and a flat portion with a constant conductor thickness, and from the front surface 51 toward the back surface 52. surface corner section (indicated by double arrow C _1), and a back surface corner portion extending from the rear surface 52 to the surface 51 direction (shown by the double arrow C _2).
FIG. 4 (b), _{R 1} to the radius of curvature of the surface corner portion _{C 1,} and the radius of curvature of the back surface corner portion _{C 2} shown in _{R _2,} and has a _R 2> R _1.
Although surface corner portion C ₁ exists in two places, the radius of curvature R ₁ respectively corresponding to the surface corner portion C ₁ of the two locations may be the same or may be different.
Although the back surface corner portion C ₂ is present at two locations, the radius of curvature R ₂ respectively corresponding to the back side corner portion C ₂ of the two portions may be the same or may be different.
The shape of the interelectrode wiring 50a shown in FIG. 4B is substantially trapezoidal as a whole, and the cross-sectional shape of the interelectrode wiring of the ceramic substrate of the present invention is such a substantially trapezoidal shape. Shape is preferred.
FIG. 4C shows an example of a cross-sectional shape in which the back surface is convex and the conductor thickness is thick at the center of the wiring.
In FIG. 4C, the cross-sectional shape of the interelectrode wiring 50a ′ includes a front surface 51 ′ and a back surface 52 ′ facing the front surface 51 ′, and a front surface corner portion (from the front surface 51 ′ toward the back surface 52 ′ ( both arrows C ₁ and a _'and indicated by), the back surface corner portions toward the surface 51' direction from the back surface 52 '(double arrow C _2' indicated by).
FIG 4 (c), 'the radius of curvature of _{R 1'} surface corner portion _{C 1,} 'the radius of curvature of _{R 2'} backside corner portion _{C 2} is indicated _by, becomes R 2 '> _{R 1'} Yes.
Incidentally, _'although there are two places, the surface corner portion C ₁ of the two _locations' surface corner portion C ₁ radius of curvature R ₁ respectively corresponding to _the' may be the same or may be different.
Also, _'although there are two places, the back side corner portion C ₂ of the two _locations' back surface corner portion C ₂ radius of curvature R ₂ that correspond to _the' may be the same or may be different.
In the interelectrode wiring 50a ′ shown in FIG. 4C, the front surface 51 ′ is flat and the back surface 52 ′ has a downwardly convex shape. Therefore, as a whole, it has a substantially trapezoidal shape with the bottom surface swelled.
The cross-sectional shape of the inter-electrode wiring of the ceramic substrate of the present invention is also preferably a substantially trapezoidal shape with such a bulging bottom surface.

In addition, the cross-sectional shape of the electrode is the same as the cross-sectional shape of the inter-electrode wiring, the front surface, the back surface, the surface corner portion having an R chamfered shape from the front surface to the back surface direction, and the back surface to the front surface direction. A back corner portion having an R chamfered shape and having a radius of curvature of the back corner portion larger than that of the surface corner portion (that is, a substantially trapezoidal shape or a substantially trapezoidal shape with an expanded bottom surface) ) Is preferable.

Hereinafter, each member which comprises the ceramic substrate of this invention is demonstrated.
A ceramic layer as an insulating layer is used for the ceramic substrate.
The material of the ceramic layer is not particularly limited, but a low-temperature sintered ceramic material is preferably used.
Examples of the low-temperature sintered ceramic material include a glass composite-based low-temperature sintered ceramic material obtained by mixing borosilicate glass with a ceramic material such as quartz, alumina, forsterite, or the like, ZnO—MgO—Al ₂ O ₃ —SiO ₂ type Crystallized glass low-temperature sintered ceramic materials using crystallized glass, BaO—Al ₂ O ₃ —SiO ₂ ceramic materials, Al ₂ O ₃ —CaO—SiO ₂ —MgO—B ₂ O ₃ ceramic materials, etc. Non-glass type low-temperature sintered ceramic material using

As a material for the electrodes and the inter-electrode wiring, a conductor material used for a ceramic electronic component using a low-temperature sintered ceramic material is preferably used.
The conductive material preferably includes a metal material. Further, a ceramic material or a glass material may be added.
The metal material preferably contains Au, Ag, or Cu, and more preferably contains Ag or Cu.
Examples of the ceramic material include alumina, titania, silica and the like.
Examples of the glass material include quartz glass and borosilicate glass.
The materials constituting the electrodes and the interelectrode wirings may be the same or different.

The thickness of the interelectrode wiring is preferably 5 μm or more and 30 μm or less.
In the region where the thickness of the interelectrode wiring is within this range, the effect of increasing the coplanarity is particularly preferably exhibited.

As the resist material, it is preferable to use a low-temperature sintered ceramic material similar to the material constituting the ceramic layer. The low temperature sintered ceramic material constituting the ceramic layer and the low temperature sintered ceramic material constituting the resist may be the same or different.
From the viewpoint of the adhesion between the resist and the electronic component mounting surface and the matching of the thermal expansion coefficients, the same material is preferable.
As will be described later, a resist that includes a low-temperature sintered ceramic material is transferred so as to straddle the inter-electrode wiring, and then baked to form a sintered resist straddling the inter-electrode wiring.

The thickness of the resist is preferably 5 μm or more and 30 μm or less.
In the region where the resist thickness is in this range, the effect of increasing the coplanarity is particularly preferably exhibited. In particular, the thickness of the resist and the thickness of the interelectrode wiring are preferably the same, and the difference between the thickness of the resist and the thickness of the interelectrode wiring is preferably 25 μm or less.

The electronic component mounted on the electronic component mounting surface of the ceramic substrate of the present invention is not particularly limited. For example, for a ceramic electronic component such as a multilayer ceramic capacitor, a multilayer inductor, or a multilayer ceramic filter obtained by integrally firing these. It is possible to apply. Also, it can be applied to semiconductor parts such as IC and memory.

Next, the manufacturing method of the ceramic substrate of this invention is demonstrated.
The method for producing a ceramic substrate of the present invention comprises a step of preparing a ceramic green sheet provided with a plurality of electrodes and an inter-electrode wiring connecting the electrodes on the electronic component mounting surface, and a resist having a resist pattern provided on the surface. A step of preparing a sheet, and the resist sheet is placed and pressure-bonded so that the resist pattern overlaps an electronic component mounting surface of the ceramic green sheet, and the resist is placed so that the resist of the resist sheet straddles the inter-electrode wiring. And a transferring step.
Since there are several modes for the step of preparing the resist sheet and the step of transferring the resist so that the resist of the resist sheet straddles the inter-electrode wiring, each mode will be described.

In the first aspect of the method for producing a ceramic substrate, a resist pattern is printed on a release film, the release film is pressure-bonded to a transfer sheet, and the release film is peeled off to form a resist pattern on the transfer sheet. A resist sheet is prepared by transfer, and a resist sheet made of a transfer sheet on which the resist pattern is transferred is placed and pressure-bonded so that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet. The sheet is peeled off, and the resist is transferred so that the resist on the transfer sheet straddles the inter-electrode wiring.
FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate.
First, a resist pattern 260 is printed on the release film 210 as shown in FIG.
The release film is a film in which a release layer is formed on a base film such as PET, and a general release film can be used.
For the printing of the resist pattern, a printing method using a resist paste, such as screen printing, photolithography, and ink jet printing, can be used. As the resist paste, a paste containing the low-temperature sintered ceramic material described as the resist material in the description of the ceramic substrate of the present invention can be used.

Next, the release film 210 is inverted so that the resist pattern 260 faces the transfer sheet 220 as shown in FIG. 5 (b), and the release film 210 and the transfer sheet as shown in FIG. 5 (c). 220 is stacked.
In FIGS. 5B and 5C and the drawings in this specification, in the drawings in which two or more sheets or films are stacked, the upper sheet or film is allowed to pass through to form a resist pattern, electrodes, and electrodes. The positional relationship of the inter-wiring is schematically shown.
Then, the overlapped release film 210 and the transfer sheet 220 are pressure-bonded, and the release film 210 is peeled off as shown in FIG. 5D to transfer the resist pattern 260 to the transfer sheet 220.
As the transfer sheet, a resin sheet such as a PET resin sheet, a foam release sheet, or a UV release sheet can be used.
In this way, a resist sheet 200 having a resist pattern 260 provided on the surface of the transfer sheet 220 is prepared.
The thickness of the transfer sheet is preferably 10 μm or more, and preferably 500 μm or less.
The pressure, temperature, and time for crimping can be arbitrarily set.

6 (a), 6 (b) and 6 (c) are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate.
Separately, a ceramic green sheet is prepared in which a plurality of electrodes and inter-electrode wiring for connecting the electrodes are provided on the electronic component mounting surface.
FIG. 6A shows a ceramic green sheet 230. The ceramic green sheet is a sheet containing a ceramic material before firing.
The ceramic green sheet can be produced as follows.
First, ceramic powder containing a low-temperature sintered ceramic material, a binder, and a plasticizer are mixed in arbitrary amounts to prepare a ceramic slurry.
This ceramic slurry is applied on a carrier film to form a sheet. An apparatus such as a lip coater or a doctor blade can be used for slurry application.
The thickness of the ceramic green sheet to be produced is arbitrary, but is preferably 5 μm or more and 100 μm or less.

The ceramic green sheet 230 is provided with an electrode 240 and an interelectrode wiring 250 on the electronic component mounting surface 10. The electrode 240 and the interelectrode wiring 250 become the electrode 40 and the interelectrode wiring 50 of the ceramic substrate 1 shown in FIG. 2 by firing.
A plurality of electrodes 240 are provided, and the plurality of electrodes 240 are connected by an interelectrode wiring 250.
Formation of the electrode 240 and the interelectrode wiring 250 on the electronic component mounting surface 10 of the ceramic green sheet 230 can be performed by a method such as screen printing, inkjet, gravure printing, photolithography, or the like.
When the ceramic substrate to be manufactured is a multilayer board, a laminated body obtained by laminating and pressing a plurality of wiring-formed ceramic green sheets can be regarded as one ceramic green sheet, and the following steps can be performed. Of the main surface of the laminate, the surface on which the electronic component is mounted becomes the electronic component mounting surface of the ceramic green sheet.

Next, as shown in FIG. 6B, the ceramic green sheet 230 is inverted so that the electrode 240 and the inter-electrode wiring 250 face the resist pattern 260 of the resist sheet 200, and the ceramic green sheet 230 as shown in FIG. The green sheet 230 and the resist sheet 200 are overlapped.
At this time, the resist pattern 260 is overlapped across the interelectrode wiring 250.
Then, the stacked ceramic green sheet 230 and the resist sheet 200 are pressure-bonded.
The pressure, temperature, and time for crimping can be arbitrarily set.

FIG. 7A and FIG. 7B are process diagrams schematically showing a part of the first aspect of the method for manufacturing a ceramic substrate.
FIG. 7A shows a state in which the bonded ceramic green sheet 230 and the resist sheet 200 are reversed so that the resist sheet 200 is on the upper side. When the transfer sheet 220 constituting the resist sheet 200 is peeled from the ceramic green sheet 230, the resist pattern 260 remains on the ceramic green sheet 230 side.
As a result, the resist on the transfer sheet is transferred so as to straddle the inter-electrode wiring.

By firing the ceramic green sheet to which the resist has been transferred as shown in FIG. 7B, the unsintered ceramic material contained in the ceramic green sheet is sintered to form a ceramic layer. In addition, the electrodes on the ceramic green sheet, the interelectrode wiring, and the resist are also fired. As a result, a ceramic substrate 1 as shown in FIG. 2 can be obtained.

Next, a second aspect of the method for manufacturing a ceramic substrate will be described.
In the second aspect of the method for producing a ceramic substrate, a resist pattern is prepared by printing a resist pattern on a firing sheet made of a material that is burned off at the firing temperature of the ceramic green sheet, and the resist pattern is printed on the firing sheet. A resist sheet made of a sheet is placed and pressure-bonded so that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet, and the firing sheet is burned out by firing the resist sheet together with the ceramic green sheet. The resist is transferred so that the resist on the baking sheet straddles the inter-electrode wiring.
The second aspect of the method for manufacturing a ceramic substrate differs from the first aspect in that a baking sheet is used as the resist sheet and the sheet portion of the resist sheet is removed by baking.
FIG. 8A, FIG. 8B, FIG. 8C, and FIG. 8D are process diagrams schematically showing a second aspect of the method for manufacturing a ceramic substrate.

First, as shown in FIG. 8A, a resist pattern 260 is printed on the baking sheet 320. As a method for printing the resist pattern on the baking sheet, the same method as the method for printing the resist pattern on the release film in the first embodiment can be used.
The firing sheet is a firing sheet made of a material that burns away at the firing temperature of the ceramic green sheet. The firing temperature of the ceramic green sheet varies depending on the composition of the ceramic material contained in the ceramic green sheet, but is generally 200 ° C. or higher and 1000 ° C. or lower.
Whether or not the firing sheet is burned off at the firing temperature is determined by the weight reduction rate when the firing sheet is held for 2 hours in a heating furnace set to the firing temperature. If the weight reduction rate is 5% or more, it is determined that the firing sheet is a sheet that burns out at the firing temperature.

As specific examples of the firing sheet, a resin-based sheet and a carbon sheet are preferably used. As an example of the resin-based sheet, an acrylic resin sheet, a polystyrene resin sheet, or the like can be used.
The thickness of the firing sheet is preferably 5 μm or more, and preferably 100 μm or less.

A sheet obtained by printing the resist pattern 260 on the baking sheet 320 becomes the resist sheet 300. Separately, the same ceramic green sheet 230 as described in the first embodiment is prepared (see the right side of FIG. 8A).

Next, as shown on the left side of FIG. 8B, the ceramic green sheet 230 is inverted so that the electrode 240 and the interelectrode wiring 250 face the resist pattern 260 of the resist sheet 300, and on the right side of FIG. As shown, the ceramic green sheet 230 and the resist sheet 300 are stacked.
At this time, the resist pattern 260 is overlapped across the interelectrode wiring 250.
Then, the stacked ceramic green sheet 230 and the resist sheet 300 are pressure-bonded.
The pressure, temperature, and time for crimping can be arbitrarily set.

FIG. 8C shows a state in which the pressure-bonded ceramic green sheet 230 and the resist sheet 300 are reversed so that the resist sheet 300 is on the upper side.
Then, the resist sheet 300 is fired together with the ceramic green sheet 230 at the firing temperature of the ceramic green sheet.
By firing, the unsintered ceramic material contained in the ceramic green sheet is sintered to form a ceramic layer.
Further, the electrodes on the ceramic green sheet and the interelectrode wiring are also fired.
At the same time, the baking sheet 320 constituting the resist sheet 300 is burned out by baking.
Since the resist pattern 260 remains without being burned off, the resist on the baking sheet is transferred so as to straddle the inter-electrode wiring.
As a result, a ceramic substrate 1 as shown in FIG. 8D can be obtained. This ceramic substrate 1 is the same as the ceramic substrate 1 shown in FIG.

Next, the 3rd aspect of the manufacturing method of a ceramic substrate is demonstrated.
In the third aspect of the method for producing a ceramic substrate, a resist pattern is prepared by printing a resist pattern on a peeling sheet that can be peeled off after pressure bonding to the ceramic green sheet. From the peeling sheet on which the resist pattern is printed, The resist sheet is placed so that the resist pattern overlaps with the electronic component mounting surface of the ceramic green sheet, and the resist sheet is peeled off, and the resist on the peeling sheet straddles the inter-electrode wiring. The resist is transferred as follows.
In the third aspect of the method for producing a ceramic substrate, a release sheet is used as the resist sheet. The third aspect is different from the first aspect in that a resist sheet is prepared by printing a resist pattern directly on a release sheet without using a release film.
FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D are process diagrams schematically showing a third aspect of the method for manufacturing a ceramic substrate.

First, as shown in FIG. 9A, a resist pattern 260 is printed on the peeling sheet 420. As a method for printing the resist pattern on the release sheet, the same method as the method for printing the resist pattern on the release film in the first embodiment can be used.
The peeling sheet is a sheet that can be peeled off after being pressed onto the ceramic green sheet. In order to enhance the peelability, a release agent such as a silicone release agent or a fluorine release agent may be provided on the surface.

As specific examples of the peeling sheet, a resin-based sheet and a carbon sheet are preferably used. As an example of the resin-based sheet, an acrylic resin sheet, a polystyrene resin sheet, or the like can be used.
The thickness of the peeling sheet is preferably 5 μm or more, and preferably 100 μm or less.

A sheet obtained by printing the resist pattern 260 on the peeling sheet 420 becomes the resist sheet 400. Separately, the same ceramic green sheet 230 as described in the first embodiment is prepared (see the right side of FIG. 9A).

Next, as shown on the left side of FIG. 9B, the ceramic green sheet 230 is inverted so that the electrode 240 and the interelectrode wiring 250 face the resist pattern 260 of the resist sheet 400, and on the right side of FIG. As shown, the ceramic green sheet 230 and the resist sheet 400 are stacked.
At this time, the resist pattern 260 is overlapped across the interelectrode wiring 250.
Then, the stacked ceramic green sheet 230 and the resist sheet 400 are pressure bonded.
The pressure, temperature, and time for crimping can be arbitrarily set.

FIG. 9C shows a state in which the pressure-bonded ceramic green sheet 230 and the resist sheet 400 are reversed so that the resist sheet 400 is on the upper side. When the peeling sheet 420 constituting the resist sheet 400 is peeled from the ceramic green sheet 230, the resist pattern 260 remains on the ceramic green sheet 230 side.
As a result, the resist on the peeling sheet is transferred so as to straddle the inter-electrode wiring.

As shown in FIG. 9D, by firing the ceramic green sheet to which the resist has been transferred, the unsintered ceramic material contained in the ceramic green sheet is sintered to form a ceramic layer. In addition, the electrodes on the ceramic green sheet, the interelectrode wiring, and the resist are also fired. As a result, a ceramic substrate 1 as shown in FIG. 2 can be obtained.

In any of the above-described methods for producing a ceramic substrate of the present invention, the ceramic substrate of the present invention can be produced.
In any aspect of the method for producing a ceramic substrate of the present invention, the resist sheet is disposed so that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet so that the resist pattern of the resist sheet straddles the inter-electrode wiring. Crimp.
By this pressure bonding, the inter-electrode wiring is pushed toward the ceramic green sheet, and a part of the inter-electrode wiring is buried in the ceramic green sheet. As a result, as shown in FIG. 3, the height of the upper surface of the resist 60a and the upper surfaces of the interelectrode wiring 50a and the

electrodes

40a and 40b around the resist 60a are aligned.
That is, according to the method for manufacturing a ceramic substrate of the present invention, a ceramic substrate having a high coplanarity around the interelectrode wiring can be obtained.

Another aspect of the ceramic substrate of the present invention is a ceramic substrate in which an electrode is provided on an electronic component mounting surface, and a resist that divides the electrode into a plurality of electrodes by straddling the electrode is disposed on the electronic component mounting surface. It is characterized by.
This aspect is different from the aspect of the ceramic substrate of the present invention described above in that the portion where the resist straddles is not an inter-electrode wiring but an electrode. The preferable aspect of another structure is the same.

FIG. 10A is a top view schematically showing a portion where a resist straddling an electrode is arranged in a ceramic substrate according to an embodiment of the present invention.
FIG. 10A schematically shows that the electrode is divided into a plurality of

electrodes

540a and 540b by arranging the resist 560 straddling the electrodes. The electrode 540a and the electrode 540b can be regarded as one electrode before the resist 560 is disposed thereon. The connection between the electrode 540a and the electrode 540b is expressed by showing a portion hidden under the resist 560 with a dotted line.

FIG. 10B is a top view schematically showing a state in which electronic components (multilayer ceramic capacitor 110a and multilayer ceramic capacitor 110b) are mounted on each of the divided electrodes.
In the ceramic substrate of the present invention of this aspect, even when the inter-electrode wiring is not provided on the electronic component mounting surface, the electrode itself can be divided into a plurality of electrodes by arranging a resist straddling the electrodes. it can. And it can be set as the electronic device which each mounted the electronic component in the some electrode.
Also in this aspect, it is possible to prevent the solder from spreading between the electrodes during component mounting.

Other aspects of the method for producing a ceramic substrate of the present invention include a step of preparing a ceramic green sheet having electrodes provided on an electronic component mounting surface, a step of preparing a resist sheet having a resist pattern on the surface, Placing the resist sheet so that the resist pattern overlaps with the electronic component mounting surface of the ceramic green sheet, and then transferring the resist so that the resist of the resist sheet straddles the electrodes. And
According to the method for manufacturing a ceramic substrate of the present invention of this aspect, the resist can be transferred so that the resist of the resist sheet straddles the electrodes. And the ceramic substrate by which the electrode was divided | segmented into the some electrode can be manufactured.
The specific mode of the step of transferring the resist so that the resist of the resist sheet straddles the electrode may be the same as the step of transferring the resist so that the resist of the resist sheet straddles the inter-electrode wiring described above. Since it can, detailed description is abbreviate | omitted.

Examples of the ceramic substrate of the present invention and the method for manufacturing the ceramic substrate of the present invention will be described below more specifically. In addition, this invention is not limited only to these Examples.

Example 1
A ceramic green sheet provided with interelectrode wiring for connecting a plurality of electrodes to each other by screen printing a conductive paste containing Cu on the ceramic green sheet was prepared.
Separately, a resist pattern containing the same ceramic material as that of the ceramic green sheet was printed on a PET release film to form a resist pattern. Then, a transfer sheet made of a PET resin sheet and a release film were stacked and pressure-bonded, and the resist pattern was transferred to the transfer sheet.
Subsequently, the ceramic green sheet and the transfer sheet were stacked and pressure-bonded so that the resist pattern straddled the inter-electrode wiring.
Further, by peeling off the transfer sheet, the resist was transferred so that the resist on the transfer sheet straddled the inter-electrode wiring.
Then, the ceramic material which comprises a ceramic green sheet was baked at the baking temperature, and the ceramic substrate was obtained.

(Comparative Example 1)
A ceramic green sheet similar to that in Example 1 was prepared. A resist paste containing the same ceramic material as that forming the ceramic green sheet was directly printed by screen printing so as to straddle the inter-electrode wiring on the ceramic green sheet.
Then, the ceramic material which comprises a ceramic green sheet was baked at the baking temperature, without performing crimping | compression-bonding, and the ceramic substrate was obtained.

(Evaluation of coplanarity)
For each of the ceramic substrates obtained in Example 1 and Comparative Example 1, the area around the inter-electrode wiring (area in the enlarged cross-sectional view shown in FIG. 3) is cross-sectional observed with an electron microscope, and the size of the step in the area is determined. Coplanarity was determined by measurement.
In the ceramic substrate produced in Example 1, a part of the interelectrode wiring was embedded in the ceramic layer, and the coplanarity around the interelectrode wiring was 5 μm.
In the ceramic substrate manufactured in Comparative Example 1, the height of the inter-electrode wiring is the same as the height of the electrode, and the resist is formed on the inter-electrode wiring. And the height of the inter-electrode wiring was higher. For this reason, the coplanarity around the interelectrode wiring has been low. The coplanarity was 30 μm.

As described above, the ceramic substrate of Example 1 can be said to be a substrate having a small measured value of coplanarity around the inter-electrode wiring (high coplanarity), so that it is possible to improve workability when mounting electronic components.

DESCRIPTION OF SYMBOLS 1 Ceramic substrate 10 Electronic component mounting surface 20 Mother board mounting surface 30

Ceramic layer

40, 40a, 40b, 40c, 40d, 40e, 40f, 540a, 540b Electrode (electrode provided in electronic component mounting surface)
45

Motherboard mounting electrodes

50, 50a, 50a′50b, 50c Inter-electrode wiring 51 51 ′ Inter-electrode wiring surface 52 52 ′ Inter-electrode wiring back

surface

60, 60a, 60b, 60c, 560 Resist 100

Electronic device

110, 110a, 110b Electronic components (multilayer ceramic capacitors)
120 Electronic parts (semiconductor parts)
200, 300, 400 Resist sheet 210 Release film 220 Transfer sheet 230 Ceramic green sheet 240 Electrode (unfired electrode)
250 Interelectrode wiring (unfired interelectrode wiring)
260 Resist pattern 320 Firing sheet 420 Peeling sheet

Claims

A ceramic substrate provided with a plurality of electrodes on the electronic component mounting surface and inter-electrode wiring connecting the electrodes,
A ceramic substrate, wherein a resist straddling the inter-electrode wiring is disposed on the electronic component mounting surface.
The ceramic substrate according to claim 1, wherein a surface of the resist straddling the inter-electrode wiring is flat.
The cross-sectional shape of the electrode and the inter-electrode wiring has a front surface, a back surface, a front surface corner portion having an R chamfer shape from the front surface to the back surface direction, and an R chamfer shape from the back surface to the front surface direction. 3. The ceramic substrate according to claim 1, wherein the ceramic substrate includes a back surface corner portion, and a curvature radius of the back surface corner portion is larger than a curvature radius of the front surface corner portion.
A ceramic substrate having electrodes provided on an electronic component mounting surface,
A ceramic substrate, wherein a resist for dividing the electrode into a plurality of electrodes by straddling the electrodes is disposed on the electronic component mounting surface.
Preparing a ceramic green sheet provided with a plurality of electrodes on the electronic component mounting surface and inter-electrode wiring connecting the electrodes;
Preparing a resist sheet provided with a resist pattern on the surface;
Placing the resist sheet in such a manner that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet and pressing the resist sheet, and transferring the resist so that the resist of the resist sheet straddles the inter-electrode wiring. A method for manufacturing a ceramic substrate.
A resist pattern is printed on the release film, and the release film is further pressure-bonded to the transfer sheet, and the resist film is transferred to the transfer sheet by peeling the release film to prepare a resist sheet.
A resist sheet composed of a transfer sheet on which the resist pattern is transferred is disposed and pressure-bonded so that the resist pattern overlaps an electronic component mounting surface of the ceramic green sheet,
Peel off the transfer sheet,
The method for manufacturing a ceramic substrate according to claim 5, wherein the resist is transferred so that the resist on the transfer sheet straddles the inter-electrode wiring.
A resist sheet is prepared by printing a resist pattern on a baking sheet made of a material that burns out at the baking temperature of the ceramic green sheet,
A resist sheet made of a baking sheet on which the resist pattern is printed is disposed and pressure-bonded so that the resist pattern overlaps an electronic component mounting surface of the ceramic green sheet,
The firing sheet is burned out by firing the resist sheet together with the ceramic green sheet,
The method for producing a ceramic substrate according to claim 5, wherein the resist is transferred so that the resist on the firing sheet straddles the inter-electrode wiring.
A resist pattern is prepared by printing a resist pattern on a peeling sheet that can be peeled off after pressure bonding to the ceramic green sheet,
A resist sheet made of a peeling sheet on which the resist pattern is printed is arranged and pressure-bonded so that the resist pattern overlaps an electronic component mounting surface of the ceramic green sheet,
Peel off the release sheet,
The method for producing a ceramic substrate according to claim 5, wherein the resist is transferred so that the resist on the peeling sheet straddles the inter-electrode wiring.
The method for manufacturing a ceramic substrate according to any one of claims 5 to 8, wherein a thickness of the interelectrode wiring is 5 袖 m or more and 30 袖 m or less.
Preparing a ceramic green sheet provided with electrodes on the electronic component mounting surface;
Preparing a resist sheet provided with a resist pattern on the surface;
Placing the resist sheet so that the resist pattern overlaps the electronic component mounting surface of the ceramic green sheet, and then pressing the resist sheet, and transferring the resist so that the resist of the resist sheet straddles the electrodes. A method for producing a ceramic substrate.